RADl()TKLt:(iKAPinC IXVESTHiATION . 253 



These suggestions will explain only the commencement of 

 the discon-tinuity. By what j^rocess the structural specific char- 

 acters are further l)uilt up I do not know, 'but, if all species have 

 a physiological as well as a morphological significance, it may be 

 broadly expressed that the structural dififerences are an expres- 

 sion of different physiological processes. 



The WinbuRG Meteorite. — At a recent meeting of 

 the Royal Society a j^aper ov " A meteoric iron from W'inburg, 

 Orange Free State." by W. A. 0. Rudge, formerly professor of 

 physics at Grey University College, Bloemfontein. was read. An 

 account was given of the structure, and (.f the mechanical and 

 magnetic properties of the meteorite, which is said to have fallen 

 in 1881. It consists of large crystals of ferrite, with veins and 

 crystals of an iron-nickel alloy, the nickel not amounting to more 

 than 3 per cent. Flakes of the alloy, being insoluable in dilute 

 acid, are easily separable from the ferrite, in the crystals of which 

 very fine crystals of the alloy are found enclosed. The material 

 stands a stress of nearly 10 tons per square inch before yielding, 

 and in the elastic limit. ^"r>ung's modulus is nearly the same as for 

 pure iron. A\'hen the metal was submitted to a pressure of 

 7,000 lb. dead load, " slip " bands were developed, showing evi-' 

 dence that twinning had been set up. The magnetic properties 

 resemble those of Swedish iron, but for moderate field strengths 

 the susceptibility is greater, but less for very strong fields. 



Radiotelegraphic Investigation. — Under the 

 auspices of the British Association a Committee has been formed 

 to organise a special investigation of the effect on the propagation 

 of electric waves of the total eclipse of the sun, which will take 

 place on the 21st August next. The eclipse will afford an excep- 

 tional and important opportunity of adding to existing knowledge 

 of the propagation of electric waves through air in sunlight and 

 in darkness, and across the boundaries of illuminated a'lrl un'llumi- 

 nated regions. It will be total along a strip extending from Green- 

 land across Norwav, Sweden, Russia and Persia to the mouths 

 of the Indus. In Russia the duration of totality will be a little 

 more than two minutes. There are two main points calling for 

 investigation during the eclipse. In the first place the propagation 

 of signal bearing waves through air in the umbra and penumbra 

 will probably obey laws different as regards absorption and refrac- 

 tion from those obeyed in illuminated air. In the second place, 

 the strength, frequency and character of natural electric waves, 

 and of atmospheric discharges, may varv. The variations may 

 occur either because the propagation of natural waves from dis- 

 tant sources is facilitated or impeded by the eclipse, or, possibly, 

 because the production of natural electric waves or atmospheric 

 discharges is. for some unknown reason, affected 1)v the eclipse. 



